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Area Forecast Discussion (AFD)

Issued by Eureka, CA (EKA)

                            
000
FXUS66 KEKA 262141
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
241 PM PDT Wed Jun 26 2019

.SYNOPSIS...A seasonably cold upper-level storm system will
gradually move east across the Pacific Northwest through Friday. 
This will yield cool temperatures across the interior, along with
scattered showers over portions of Del Norte and Humbodlt Counties.
Thereafter, temperatures are forecast to moderate over the 
weekend into the middle of next week.

&&

.DISCUSSION...A closed upper-level low was positioned in the
vicinity of the Oregon coast Wednesday afternoon. Westerly 
onshore flow was aiding in cool humid conditions over northwestern
California, with interior temperatures generally in the 60s to low
70s. Similar conditions are expected during Thursday afternoon. In
addition, patchy frost will be possible tonight and Thursday night
as mainly clear skies develop across wind sheltered valleys in 
Trinity County. Otherwise, moderately steep lapse rates combined
with a moist environment will continue to aid in isolated to 
scattered shower development over portions of Humboldt and Del 
Norte Counties through Thursday afternoon.

After Thursday...the previously mentioned upper-low is forecast 
to exit northeast toward the northern Rockies, with troughing
continuing in its wake over the west coast. Model guidance shows
troughing evolving into quasi-zonal flow aloft that should be
supportive of warmer and drier conditions this weekend into the
middle of next week.

TDJ/JMG

&&

.AVIATION...A low offshore the Oregon coast will maintain a well 
mixed layer near the surface. This along with brisk SW flow aloft 
should limit the coverage and duration of IFR conditions. Granted 
there has been local pockets of shallow moist air and brief 
IFR/LIFR near the coast impacting the coastal terminals from time 
to time. Thus, brief IFR cannot be ruled out completely at the 
coastal terminals, though VFR/MVFR will most likely be the 
prevailing condition.

&&

.MARINE...A surface low offshore Oregon waters will maintain 
light southerly winds across mainly the northern waters trough 
Friday. The low will start to fill and drift northward on Friday 
allowing light to moderate northerlies to return over the weekend.
Short period seas are expected to remain low through the week and
then increase slightly over the weekend, mainly south of Cape 
Mendocino, as northerly winds increase. 

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...None.
NORTHWEST CALIFORNIA COASTAL WATERS...None.
&&

$$

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